ive been writing a movie script but it isn't finished, how would i publish it and can anyone do it at any age?

ive started to write a film script it isn't finished yet but when i do
finish it im pretty sure of sending it to a studio and see if they
like it. can anyone send anything at any age. im 13 and my friends
like it so far, i don't want mum reading it because there issomthingg
idon'tt want her to know about but, could i send it to like warnerbros
or somthing like that? if so how would i do it?